The cardiorenal syndrome is a complication in patients hospitalized with chronic heart failure (CHF). The β 2-microglobulin (b2M) level is an index of decreased glomerular filtration rate (GFR), tissue turnover and inflammation. It is an emerging new predictive marker of cardiovascular events and mortality, but its role as a biomarker of cardiorenal remodeling and failure is still unknown. TIMP1, an endogenous tissue inhibitor of activated matrix metalloproteinases, is a biomarker of heart remodeling and failure. We aimed to evaluate the circulating profile of b2M and TIMP1 in CHF patients, in sedentary controls with no tissue remodeling and in veteran athletes with physiological cardiorenal remodeling and athlete's heart (AH). We investigated the plasma levels of b2M and TIMP1 in 24 subjects with CHF without primitive renal disease, in 25 sedentary controls and in 30 veteran marathoners with AH over 50 years. The b2M and TIMP1 levels were higher in CHF patients, and there was a correlation between them (r= 0.5287, p< 0.0095). The b2M level correlated with the severity of cardiorenal impairment: with proBNP (r= 0.66, p> 0.0007), percent ejection fraction (r=-0.56, p= 0.0162) and GFR (r= 0.83, p< 0.0001). b2M was also correlated with TIMP1 in AH subjects (r= 0.7548, p< 0.0001) but not in controls. This correlation was independent from GFR in both CHF patients and sedentary controls. In CHF patients, the plasma levels of b2M and TIMP1 were linked together and correlated with the severity of cardiorenal failure. Moreover, a strong correlation between b2M and TIMP1 characterized cardiovascular remodeling not only in CHF patients but also in AH subjects. These findings suggest that clinicians should use b2M and TIMP1 as associated biomarkers of cardiorenal remodeling and failure.© 2014 S. Karger AG, Basel